All visitors to Russia need to be aware of the rules governing entry, stay and exit of foreigners in force in the country. While rules governing issue and extension of visas are also disseminated on respective websites of the Russian Embassies/Consulates; they are also avalable on the link below:

http://www.fms.gov.ru/useful/formvisa/index_eng.php

Specifically, if a foreigner intends to engage in remunerative employment or seek a job permit, the rules governing this including procedure to be adopted while arriving (filling up of migration card etc) and immediately upon entering  (registering with the office of Federal Migration Service) and other details are available at the following link:

http://www.fms.gov.ru/useful/novisas/index_eng.php

Importantly, all visitors need to register themselves with the office of the Federal Migration Service. This applies to all kinds of vistors including tourists. While, normally the concerned hotel where the tourist is put up automatically does the registration for the guest, it is worthwhile to double check from the hotel that it has indeed done so for the visitor. For other types of visitors the 'host party' or 'inviting party' is responsible for the registration. Detailed rules regarding the same are available at the following link:

http://www.fms.gov.ru/useful/migrate/index_eng.php

It is important that all visitors comply with the relevant regulations for foreigners, particularly that of registration as otherwise the visitor is likely to face difficulties at the time of departure.